OBJECTIVE: To examine the developmental changes in glutamate release. RESULTS We measured glutamate release from the S-ME through the onset of puberty. Glutamate release (74.3q8.6 ng/ml) in prepubertal monkeys (n=10) was low, and it increased to 158.3q22.3 ng/ml and 122.8q22.4 ng/ml in early pubertal (n=8) and midpubertal (n=14) monkeys, respectively. LHRH levels measured in the same samples were very low (1.4 q 0.1 pg/ml) in prepubertal monkeys, increased to higher levels (4.9 q 0.7 pg/ml) in early pubertal monkeys, with the highest LHRH levels (6.5 q 1.1 pg/ml) occurring in midpubertal monkeys. These are exciting results, since an increase in glutamate may contribute to the increase in LHRH release during the pubertal process. FUTURE DIRECTIONS In addition to LHRH and glutamate, we will measure GABA in the same samples. KEY WORDS glutamate, LHRH, GABA